Earlier this month, progressive lawmakers refused to withhold their votes on must-pass COVID-19 stimulus legislation until the bill included a $15 minimum wage. A few weeks later, conservative Democratic lawmakers are now threatening to withhold their votes on must-pass infrastructure legislation until the bill includes large tax cuts for the wealthy.

The contrast in tactics spotlights a decisive asymmetry in congressional politics right now: the right wing of the Democratic Party is willing to play hardball on behalf of the affluent, to the point of threatening to take down one of President Joe Biden’s signature legislative initiatives, an infrastructure and climate plan he will detail on Wednesday.

By contrast, the left wing of the party has not yet been willing to play the same kind of hardball on behalf of the working class — and that refusal ultimately helped kill a promised wage hike in the recent pandemic aid bill and could similarly imperil other progressive priorities.